456 Scientific Proceedings, Royal Dublin Society. 
species have been described from the Solenhofen lithographic 
stone, and among these are four referable to the genus Uropetala, 
now confined to New Zealand. It would seem, therefore, that we 
have here striking proof of the truth of Wallace’s' explanation of 
the discontinuous range of animals in far southern lands: that 
they are the last survivors of groups that at one time inhabited 
the great northern continents. Were fossil evidence available in 
other cases, such, for instance, as that of the earthworms common 
to New Zealand and Patagonia, it would possibly be found 
equally needless to imagine a sunken continent in order to explain 
the facts. 
1 Op. cit., pp. 525, 526. 
